Relationship between evolution-extinction-recovery and redox-climate changes

2015 Fiscal Year Final Research Report

• Project/Area Number: 25247084
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Tohoku University
• Principal Investigator: Kaiho Kunio 東北大学, 理学(系)研究科(研究院), 教授 (00143082)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 大量絶滅 / 大進化 / 酸素 / すす / バイオマーカー / 古気候 / 大気海洋 / エアロゾル

Outline of Final Research Achievements

Organic molecules derived from the earliest life have been detected from the oldest shallow-sea sedimentary rocks from Labrador, Canada, the age of which is >3.95 Ga. Local oxic conditions at 2.7 Ga, and subsequently global oxidation at 2.6-2.2 Ga. Oceanic redox changes played a crucial role in driving the evolution and extinction of early animals during 635-520 Ma. The low oxygen surface water accompanied by the shortage of bioessential elements and massive soil, mud, and nutrient intrusion in the oceans contributed to the main extinction at the end of the Permian. At the Cretaceous/Paleogne boundary, the stratospheric aerosol caused sufficiently colder climates at the mid-high latitudes and draught at low latitudes on land and surface water cooling with limited cessation of photosynthesis in oceans for several years, which caused the mass extinction.

Free Research Field

古生物学, 地球化学